Xr 600 R Bog

[danny v]

I have a question,my bike has a bad hesatation off the bottom and 1/3 throttle.When you hit it hard the motor hesatates than takes off very strong.Also at a stop sign it will slowly raise the idle on its own to maybe 1800 rpm than you hit the throttle quick and it drops back to normal,than slowly raises back up. is this the fuel mix screw or the needle ? main is 160,pilot is 65,UNI filter,flushed carb and tank installed in line filter and the valves just adjusted.So far what i am reading you can not get good top and bottom response on the XR 600 R. It is a 1998.The bike runs well,starts very easy its only the bad hesatation that is making me carazy !!! Thanks for your input anyone ?

Danny V

[Coolidge]

Hey Danny. I have a 97 XR600R, and recently did jetting mods per Scott Summers suggestion: 155 main/68 slow jet, fuel screw 2.5 turns out. My XR's engine is stock. I run a Pro-Circuit T-4 slip-on, UNI filter and airbox is uncorked. The low-end response (pretty much where yours is bogging) is super strong and crisp. Wheelies really easy too. I believe on the 98 model, the intake manifold was changed (more restrictive), and was even leaner box-stock. There was a pre-98 intake manifold on Epay recently. Intake change might be worth looking into? Good luck

[Kawabuggy]

The "creeping" idle, and bog on acceleration can often times be caused by a vacuum leak. Before you start swapping parts, check the simple stuff first.

Are all the hose clamps tight? Have you checked the boots for cracks or holes?

There is a method in which you start the engine, get it up to temp, and then start spraying either WD-40, or some other cleaner/penetrant, around the carb & intake boots to identify a leak.

Hope you find your problem!

[danny v]

Thanks guys for the input. I have a 160 main,65 pilot.The air box with uni is open at top.I am not sure where i left the fuel screw but I will check.This is the second time I have heard about the intake,I will shurly look into that now !!! Do you think it is possible it is my fuel screw only ?I have a white bro.E series pipe with 6 discs and the spark aresstor plate installed with a stainless header

[tgstoken]

I second the notion of an air leak on the engine side of the carb.

[FZ1426]

After checking the vacuum issue (including headpipe torque) go with a 68 pilot (for sea level) 2- 2.5 turns on the idle screw, needle at the third clip and 8-9 discs in the supertrapp.

The bogging is a lean condition at part throttle, the 8-9 discs will improve mid-upper range.

[danny v]

Thanks I will try to make those changes tomarrow. I all ready have 6 more discs that I bought that I never used. How bad will it hurt my bottom end if I remove the spark arrestor plate and just run the end cap ?

[pwrpapa]

I second the notion of an air leak on the engine side of the carb.

x3 for the intake leak.

[martinfan30]

Thanks I will try to make those changes tomarrow. I all ready have 6 more discs that I bought that I never used. How bad will it hurt my bottom end if I remove the spark arrestor plate and just run the end cap ?

not enuff to notice. you get enough backpressure from the bend in the header.

[creeky]

If you are suspecting the vacuum leak, check where the carb adapter is bolted to the head. The O-ring seal has been known to deteriorate and allow an intake leak.

[martinfan30]

you can also spray some carb. clean around the area and see if the RPM's change.

[FZ1426]

Thanks I will try to make those changes tomarrow. I all ready have 6 more discs that I bought that I never used. How bad will it hurt my bottom end if I remove the spark arrestor plate and just run the end cap ?

You will lose the best part of the power these motors make, which is to say very low to midrange torque. I have experimented extensively over the years and have found 8 disks to be the right number to exploit the "sweet spot" of power delivery. Any more and you will experience diminishing returns by way of trying to rev out a very friction/mass laden head coupled to a long stroke.

A good way to waste the qualities of this motor...figuratively and literally.

[danny v]

Hi guys, today I had my fuel screw out 1 1/2 turns. So I tried the 2 1/2 out and it did make a differance. I counted 7 discs in the white bro. E Series pipe. Tomarrow i will add one more like suggested and see the differance. Than I will try the 68 s jet,I bought a few last mo.I also need to check the needle position. Wasen't it you martin that said you made a little tool to remove the clip from the needle without taking the carb all the way down ? I think part of the problem is me ! I throttle it like the CR 500,which by what you are all saying is a no no ! not to mention it is a tire eater I just need to spend more time on it. The wheelies are awsome !! I get lucky and a lot of times I go from 2ed into 3ed in the air, reminds me of the CR days. I do notice the rear tire is showing wear,when I bought it looked new but I can see wear on it now. Thanks for the tire info I will check it out soon because if i don't learn to throttle it better it will put me in the poor house soon On the note of the spark arrestor I just thought it would be a little louder and deeper sounding that would be cool but I do not want to loose the bottom either, it was only a thought.

Thanks to all Danny

[danny v]

I took out the diccs and the end cap from the e series WB pipe and the bike responded like WOW !

with 14/48 every ime I twist the throttle the front tire goes up in relation to twist in 2ed gear and going hard into third I get some air as well. I am very suprised with this howeverit is noticably louder. I don't care but the police will look at the noise I think. main160,s jet 65 needle ?? Because I bought the XR used it is like a box of chocolats,you dont know what you are going to get.

How do I know if this bike has a cam in it ? Yes I know it has one but which one ? Any markings, are the lobes ground more off center so i might here a erratic idle ? When it gets up mid range to the top it just turns on and screems ! I am just affraid now to leave it loud because of the police so i might put 8 discs,spark arrest plate and cone back on tomarrow and see if I still feel a differance.

Thanks guys for your great response. I will post my findings tomarrow

Danny V

[Coolidge]

Cool

[XR_RON]

From what I have gotten from experience,the bike is a 600,your not gonna notice that much off the bottom,as say a 250,its twice the size,I jetted my 86 XR600 for all the top I could get plus gearing to,I got tired of the 2 stroke guys talking crap,then it was fast top end,and the flat spot off the bottom was gone ,XRs only did the work.

[martinfan30]

Hi guys, today I had my fuel screw out 1 1/2 turns. So I tried the 2 1/2 out and it did make a differance. I counted 7 discs in the white bro. E Series pipe. Tomarrow i will add one more like suggested and see the differance. Than I will try the 68 s jet,I bought a few last mo.I also need to check the needle position. Wasen't it you martin that said you made a little tool to remove the clip from the needle without taking the carb all the way down ? I think part of the problem is me ! I throttle it like the CR 500,which by what you are all saying is a no no ! not to mention it is a tire eater I just need to spend more time on it. The wheelies are awsome !! I get lucky and a lot of times I go from 2ed into 3ed in the air, reminds me of the CR days. I do notice the rear tire is showing wear,when I bought it looked new but I can see wear on it now. Thanks for the tire info I will check it out soon because if i don't learn to throttle it better it will put me in the poor house soon On the note of the spark arrestor I just thought it would be a little louder and deeper sounding that would be cool but I do not want to loose the bottom either, it was only a thought.

Thanks to all Danny

wasnt me about the clip. its just as easy for me to pull it all the way out, i have no air boot from the airbox anymore!

[Denn10]

put all 12 discs in and see how you like that, My L has 12 and stock gearing and i still pull front tire from takeoffs on street. I took my end cap off my WB E2 and it sounded like crap. Im sure with 12 discs youll be happy with noise control and still have great throttle reponse and torque with that 14/48 gearing

[danny v]

Ok, I put the 12 discs in with the spark arrestor plate and it runs well. It is much less on noise however the performance is lost over the open pipe. With out the plate and discs I notice the differance ( thats just me ). I am afraid to run the white brother pipe open because I do not want a ticket. I have the first gen. WB E series pipe. So at this point;12 discs are good with the spark plate. what is the max discs I can run ? 6 more ? I am very happy now that I have the bike running it is a blast to ride.It starts easy for the first time and when it is warm it starts first kick always ! Drawback : It kills knobbies quick !!!!!!! I am going to try the MT 21s or the MT 22s for the rear.If that does not do well I will put the dunlop 606s and see how they work. I think I ride hard on the street,take offs are hard.

Thanks for the help guys.

Danny V

[Denn10]

when i took my end cap off completely and straight out open i didnt notice any power gain but different bikes too, i have thought about more discs, prolly wont ever try, but you could try more just need to find a bit longer bolts. Be our test dummy LOL